Light Pollution from Seen from Space Appears Worse with LED Streetlights than HPS Models

Photos before and after LED an LED streetlight installation from the International Space Station (ISS) show increased light pollution form LED-based street lights in Milan, Italy. The feature article detailing the two photos from ISS was first described in AstronomyNow.com.

Image of Milan taken from ISS 2012

Image of Milan taken from ISS 2012 (Before LED Streetlight Installation)

The LED streetlight installation shows brighter lighting in the center of Milan after installation of LED-based streetlights. While LED-based streetlights offer better quality light than the high-pressure sodium lights that they often replace, the better quality light comes from more blue and green light emission. This leads to worse light pollution such as sky glow, at least according to ISS astronauts.

Image of Milan taken from ISS in 2015 (After LED Streetlight Installation)

Image of Milan taken from ISS in 2015 (After LED Streetlight Installation)

A new study called the Cities at Night project will connect ground-based night sky light measurement with digital images from the International Space Station of cities around the world. The digital images are calibrated against the brightness of stars above ISS and the brightness of the night sky measured on the ground. Scientists from the Universidad Complutense de Madrid, Spain and the Cégep de Sherbrooke in Canada, and members of the public will collaborate on the project.